Air cavity packages are usefully employed to house semiconductor die and other microelectronic devices supporting radio frequency (RF) functionalities. Notably, air cavity packages may provide certain performance benefits when housing microelectronic devices operable at relatively high radio frequencies, such as radio frequencies exceeding 100 megahertz and possibly approaching or exceeding 2.1 gigahertz. By conventional design, a leaded air cavity package includes a base flange, a window frame, a plurality of leads, and a cover piece, which are assembled and bonded in a stacked configuration. The base flange may serve as a substrate, a heat sink, and an electrically-conductive terminal of the package. Accordingly, the base flange may be realized as a monolithic or multilayer structure, which is predominately composed of copper or another metal having a relatively high thermal conductivity. In contrast, the window frame is produced from a dielectric material, such as a ceramic, to provide electrical insulation between the base flange and the package leads. The window frame may have a rectangular planform geometry and a central opening, which helps define an outer perimeter of the sealed air cavity. The cover piece is bonded over the window frame and package leads to enclose the air cavity. Prior to attachment of the cover piece, one or more microelectronic devices (e.g., RF semiconductor die) are installed within the air cavity, attached to an upper surface of the base flange, and electrically interconnected to the package leads by, for example, wirebonding.
For simplicity and clarity of illustration, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the subsequent Detailed Description. It should further be understood that features or elements appearing in the accompanying figures are not necessarily drawn to scale unless otherwise stated. For example, the dimensions of certain elements or regions in the figures may be exaggerated relative to other elements or regions to improve understanding of embodiments of the invention.